Friction stabilizer with tabs

ABSTRACT

A friction stabilizer having tabs comprising a tubular body comprising an exterior surface and having a first portion and having a second portion provided with a taper. The first portion has an impact end and the second portion has an insertion end. A tab is on the tubular body and extends outward from the exterior surface of the tubular body in a direction toward the impact end and away from the insertion end of the tubular body. The tabs can be rectangular shaped or triangular shaped or have other shapes which prevent the friction stabilizer from being removed from a drilled bore in a mine. When the friction stabilizer with tabs is inserted into a drilled bore in a mine, the tabs do not impede insertion. But, after insertion into the drilled bore the tabs resist removal of the tubular body, and thus allow the stabilizer to support the mine wall or ceiling. The friction stabilizer is made by taking a steel coil and punching the shape of the tabs in the metal, for example sheet metal, unrolled from the coil. A notch is also punched into the sheet at a predetermined location. Rolling die roll the tubular body, and a cutting machine cuts the tubular body at the notches, so tubular bodies of predetermined length are cut. The tabs extend from the exterior surface of the tubular body due to the natural spring constant of the steel or metal from which the tubular body is made. A weld ring is welded to the impact end and has a weld ring gap space.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Provisional U.S. Patent Application No. 60/507,366 to Valgora, and filed on Sep. 30, 2004, for a “Friction Stabilizer With Tabs.”

BACKGROUND

Cave-ins are a constant threat associated with underground mining operations. It is difficult to predict when and where a cave-in will occur. Typically, workers are provided with little or no warning prior to a cave-in, and thus they have a minimal amount of time to react to a cave-in. Indeed, mine walls or ceilings that appear fine upon visual inspection may have significant fractures just below their surfaces, making them structurally weak and prone to collapse. Cave-ins are very destructive and may result in miners becoming trapped and/or injured. Additionally, equipment and machinery may be damaged or destroyed.

Friction type stabilizers have been used in mining operations to stabilize walls and ceilings of the mine. Such stabilizers are pounded into bores drilled in mine walls and ceilings. The stabilizers form a friction fit with the drilled bore. But, these stabilizers may slide out of the drilled bores when the rock wall or ceiling shifts/moves, and in such situations the stabilizers are unable to prevent a mine wall or ceiling cave-in.

Therefore, it would be desirable to provide a new and improved stabilizer that decreases the likelihood of a cave-in. It would also be desirable if the stabilizer was compatible with existing mining equipment and inexpensive to fabricate.

SUMMARY

The friction stabilizer with tabs according to this invention is used to secure the walls and ceilings of mines to thus prevent a cave-in from occurring. The friction stabilizer with tabs comprises a hollow body, preferably tubular. The tubular body comprises an impact end, an insertion end, a first portion and a second portion. The second portion has a notch and is tapered.

The tubular body has an interior and an exterior surface, and tabs are connected to and extend from the tubular body. The tabs extend in a direction leading away from the insertion end of the tubular body and in a direction leading towards the impact end of the tubular body. The tabs each make an acute angle with the exterior surface of the tubular body. The tabs can be rectangular shaped and there can be three such tabs extending from the exterior surface of the tubular body. Each rectangular shaped tab further comprises parallel tab side edges and a tab free edge connecting between the tab side edges.

In other embodiments, the tabs may be triangular shaped tabs, curved shaped tabs, polygonal shaped tabs, U-shaped tabs, tabs having both curved portions and linear portions, semi-circular shaped tabs, hook shaped tabs, parabolic shaped tabs, and combinations of the above. Also, the tabs can be of any shape that inhibits the withdrawal of the friction stabilizer with tabs from the drilled bore in a mine. The above-described tabs are punched into the sheet from which the tubular body is formed by a punching machine, thus they are joined to the tubular body at bends.

The tubular body further comprises a first gap space wall and a second gap space wall spaced apart from one another by a tube gap space. The tube gap space is used for allowing the tubular body to be compressed radially inward when the tubular body is driven into a drilled bore in a mine having, the drilled bore having a diameter less than the outer diameter of the tubular body.

The friction stabilizer further comprises a weld ring having a weld ring gap space, and the weld ring is joined to the tubular body such that the weld ring gap space and tube gap space are aligned. The weld ring is joined to the exterior surface of the first portion of the tubular body at the impact end of the tubular body by, for example, a weld. The weld ring gap space is used for allowing the weld ring to be compressed radially inward. The weld ring can have a rectangular cross section or a circular cross section.

To use the friction stabilizer with tabs, a drilled bore is made in the wall or ceiling of the mine. The wall is sufficiently solid and of sufficient thickness to accommodate a bore of sufficient length, and the drilled bore has a diameter slightly less than the diameter of the tubular body. A support plate having an opening is provided, the opening being sized such that the tubular body can pass through the opening. The opening in the plate is aligned with the drilled bore. The tapered end of the tubular body is aligned with and inserted through the opening in the plate and into the drilled bore so that the taper of the tubular body is received in the drilled bore.

Then a pneumatic or hydraulic hammer or some other means for hammering is used for pounding or driving the stabilizer with tabs into the drilled bore. As the stabilizer with tabs is driven into the drilled bore the tabs move or flex inwardly towards the exterior surface of the tubular body. This allows the friction stabilizer with tabs to be hammered into the drilled bore without the tabs impeding movement. During the pounding process the plate becomes trapped between the weld ring and the surrounding ceiling or wall of the mine, as the case may be. Additionally, the tubular body compresses and the gap space distance decreases as the friction stabilizer is driven into the drilled bore. Then, if loading force is applied to remove the tubular body with tabs, the tabs immediately dig into the surrounding wall which surrounds the drilled bore, making the removal of the tubular body significantly more difficult. Such loading force may come from the plate that is providing support. Thus, if the ceiling or wall begins to cave-in, the tabs will keep digging into the surrounding wall, and the friction stabilizer having tabs continues to work against a cave-in. This digging-in action could stop a cave-in progress or limit the severity of a cave-in. Additionally, the digging-in action could provide miners with extra time to get out of harms way, or provide inspectors with time so that they can conduct an on site inspection.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an elevational view of the friction stabilizer having tabs.

FIG. 2 is a side elevational view of the friction stabilizer having tabs.

FIG. 3 is a bottom plan view of the friction stabilizer having tabs.

FIG. 4 is a top plan view of the friction stabilizer having tabs.

FIG. 5 is a sectional view of the friction stabilizer having tabs taken along cut line 5-5.

FIG. 6 is a sectional view of the friction stabilizer having tabs taken along cut line 6-6.

FIG. 7 is a top plan view of the strip of steel used to manufacture the friction stabilizer having tabs.

FIG. 8 shows a bottom plan view of a second embodiment of the friction stabilizer with rectangular tabs according to a second embodiment of the invention.

FIG. 9 shows a side elevational view of the second embodiment of the friction stabilizer with rectangular tabs.

FIG. 10 shows a top plan view of the second embodiment of the friction stabilizer with rectangular tabs.

FIG. 11 shows a sectional view of the second embodiment of the friction stabilizer with rectangular tabs taken along cut line 11-11 in FIG. 10.

FIG. 12 shows a sectional view of the second embodiment of the friction stabilizer with rectangular tabs taken along cut line 12-12 in FIG. 8.

FIG. 13 shows a bottom plan view of a third embodiment of the friction stabilizer with tabs.

FIG. 14 shows a side elevational view of the third embodiment of the friction stabilizer with tabs.

FIG. 15 shows a top plan view of the third embodiment of the friction stabilizer with tabs.

FIG. 16 shows a sectional view of a third embodiment of the friction stabilizer with tabs taken along cut line 16-16 in FIG. 15.

FIG. 17 shows a sectional view of the third embodiment of the friction stabilizer with tabs taken along cut line 17-17 in FIG. 13.

FIG. 18 shows a bottom plan view of a fourth embodiment of the friction stabilizer with tabs.

FIG. 19 shows a side elevational view of the fourth embodiment of the friction stabilizer with tabs.

FIG. 20 shows a top plan view of the fourth embodiment of the friction stabilizer with tabs.

FIG. 21 shows a sectional view of the fourth embodiment of the friction stabilizer with tabs taken along cut line 21-21 in FIG. 20.

FIG. 22 shows a sectional view of the fourth embodiment of the friction stabilizer with tabs taken along cut line 22-22 in FIG. 18.

FIG. 23 shows a bottom plan view of a fifth embodiment of the friction stabilizer with tabs.

FIG. 24 shows a side elevational view of the fifth embodiment of the friction stabilizer with tabs.

FIG. 25 shows a top plan view of the fifth embodiment of the friction stabilizer with tabs.

FIG. 26 shows a cross sectional view of the fifth embodiment of the friction stabilizer with tabs taken along cut line 26-26 in FIG. 25.

FIG. 27 shows a cross sectional view of the fifth embodiment of the friction stabilizer with tabs taken along cut line 27-27 in FIG. 23.

FIG. 27A shows a top plan view of a of a sixth embodiment of the friction stabilizer with tabs having a plurality of differently shaped tabs.

FIG. 28 shows a diagrammatic view of the manufacturing process used for manufacturing the friction stabilizer with tabs.

FIG. 29 is a top plan view of the weld ring having a circular shaped cross section.

FIG. 30 is a sectional view taken along cut line 30-30 in FIG. 29 of the weld ring having a circular shaped cross section.

FIG. 30 a is a view, partly in section, of the circular weld ring and tubular body joined together with a weld.

FIG. 31 is a top plan view of the weld ring having a rectangular shaped cross section.

FIG. 32 is a sectional view taken along cut line 32-32 in FIG. 31 of the weld ring having a rectangular shaped cross section.

FIG. 32 a is a view, partly in section, of the rectangular weld ring and tubular body joined together with a weld.

FIG. 33 is a top plan view of the planar plate.

FIG. 34 is a sectional view of the planar plate taken along cut line 34-34 in FIG. 33.

FIG. 35 is a top plan view of the domed plate.

FIG. 36 is a sectional view of the domed plate taken along cut line 36-36 in FIG. 35.

FIG. 37 is a sectional view of a mine showing friction stabilizers having tabs deployed in the mine.

DESCRIPTION

At the outset, it noted that like reference numbers are intended to identify the same structure, portions, or surfaces consistently throughout the figures. It is also noted that when the term “about” is used in connection with describing a number that the number includes numbers in decimal form that can be rounded to that number.

Shown generally in FIGS. 1-6 is the friction stabilizer 20 with tabs 25. FIG. 4 shows a top plan view of the friction stabilizer with tabs 20. As shown in FIGS. 1 and 3, the friction stabilizer with tabs 20 comprises a tubular body 22 having tabs 25 extending therefrom. The tubular body 22 is elongate and has a first portion 33 and a second portion 34. The second portion 34 is formed integral joined to the first portion 33, and the second portion 34 has a taper 35. The tubular body 22 has an impact end 30 and an insertion end 32 that are spaced from one another by the length, designated L in FIG. 4, of the tubular body 22. The taper 34 extends from the insertion end 32 in a direction toward the impact end 30, until it reaches the first portion 33. The tubular body 22 may comprise a total length L of about sixty inches, about four inches of which comprise the second portion 34 having the taper 35.

The tubular body 22 further comprises an interior surface 24 and an exterior surface 26, as shown in FIGS. 3 and 5. The interior surface 24 defines a stabilizer interior 23 internal to the tubular body 22.

As further shown in FIGS. 3 and 5, the tubular body 22 has a first gap space wall 27 and a second gap space wall 29 which are spaced apart from one another. The first and second gap space walls 27, 29, respectively, extend along the length L of the tubular body 22, from the impact end 30 of the tubular body 22 to the insertion end 32 of the tubular body 22. The first and second gap space walls, 27, 29, respectively, define a tube gap space 28 between them, that extends in the direction of the of the longitudinal axis, designate X in FIG. 2, of the tubular body 22. As shown in FIGS. 3 and 5, the tube gap space 28 extends along the length L of the body 22, from the impact end 30 to the insertion end 32 of the tubular body 22. The tube gap space 28 defined between the first and second gap space walls 27, 29 is used for allowing tubular body 22 to be compressed radially inward. In a manner to be described presently, the diameter designated D in FIG. 5, of the tubular body 22 decreases when the tubular body 22 is driven into a drilled bore 50 formed in a wall 52 or ceiling 54 of a mine 56, as shown in FIG. 37. The drilled bore 50 has a bore diameter 51, designated B in FIG. 37, that is less than the diameter D of the tubular body 22.

A notch 36 is defined in the taper 35 of the second portion 34 of the tubular body 22. The notch 36 allows the taper 35 to be formed in the tubular body 22 at the insertion end 32 thereof when the tubular body 22 is being rolled. The taper 35 is used for allowing the insertion end 32 of the tubular body 22 to be initially fitted or inserted into the drilled bore 50. After the taper 35 is fitted into the drilled bore 50, the impact end 30 of the tubular body 22 can be pounded causing the tubular body 22 to move into the drilled bore 50.

In accordance with the invention, the tubular body 20 comprises tabs 25 that extend from the exterior surface 26 in a direction toward the impact end 30 of the tubular body 20, and away from the insertion end 32 of the tubular body 22. The tabs 25 work against the removal of the tubular body 22 from a drilled bore 50 in a mine 56. As a result, the tabs 25 advantageously decrease the likelihood of a mine 56 cave-in, as will be described presently.

In a preferred embodiment, the tabs 25 are embodied to be rectangular shaped tabs 40. In particular, there is a first rectangular shaped tab 40 a, a second rectangular shaped tab 40 b, and a third rectangular shaped tab 40 c. The first rectangular shaped tab 40 is positioned closest to the insertion end 32 of the tubular body 22, and the third rectangular shaped tab 40 c is positioned farthest from the insertion end 32 of the tubular body 22, as shown in FIG. 4. The second rectangular shaped tab 40 b is positioned between the first and second rectangular shaped tabs 40 a, 40 c, respectively. The first, second, and third rectangular shaped tabs 40 a, 40 b, and 40 c respectively, are punched out of, laser cut, or otherwise formed in the tubular body 22, in a method to be described presently.

The first, second, and third rectangular shaped tabs 40 a, 40 b, and 40 c, respectively, extend outward from the exterior surface 26 of the tubular body 22. Each rectangular shaped tab 40 a, 40 b, 40 c comprises two parallel tab side edges 43 and a tab free edge 45 that extends between the tab side edges 43, as shown in FIG. 7, which is a top plan view of the flat strip of metal 102 from which the tubular body 22 is formed. The tab side edges 43 and tab free edges 45 are shown in FIGS. 1, 6, and 7. It is noted that the tabs 40 a, 40 b, and 40 c shown throughout FIGS. 1-6 are structurally the same.

Each of the rectangular shaped tabs 40 a, 40 b, and 40 c, respectively, is joined to the tubular body 22 along a bend 44, with the bend being opposite the tab free edge 45. The bends 44 are closer to the insertion end 32 of the tubular body 22 than the tab free edge 45. Each of the rectangular shaped tabs 40 a, 40 b, and 40 c, respectively, makes an acute angle with the exterior surface 26 of the tubular body 22, as shown in FIG. 2. Also, the rectangular shaped tabs 40 a, 40 b, and 40 c, respectively, extend in a direction leading away from the insertion end 32 of the tubular body 22, and in a direction leading toward the impact end 30 of the tubular body 22, as shown in FIG. 2. The rectangular shaped tabs 40 a, 40 b, and 40 c, respectively, are spaced apart from one another along the tubular body 22, and are formed in the tubular body 22 such that they are opposite to the tube gap space 28, as shown in FIG. 6. It is further noted that there are openings 48, as shown in FIG. 2, in the tubular body 22 under the rectangular shaped tabs 40 a, 40 b, and 40 c, respectively, where they extend from the exterior surface 26.

Then, when the tubular body 22 is pounded into a drilled bore 50 insertion end 32 first, the rectangular shaped tabs 40 a, 40 b, and 40 c, respectively, bend inward along their bends 44 in a direction toward the openings 48 in the tubular body 22. In other words, the rectangular shaped tabs 40 a, 40 b, and 40 c, respectively, move back into the tubular body 22 from which they were punched, and thus they do not impede the tubular body 22 from being pounded into the drilled bore 50 in the wall 52 or ceiling 54 of the mine 56, as shown in FIG. 37. Then, in the event of a mine cave-in or wall collapse, the tubular body 22 advantageously remains in place and supports the mine wall 52 or ceiling 54, since the rectangular shaped tabs 40 a, 40 b, and 40 c, respectively, resist removal from the drilled bore 50 and dig into the surrounding rock. This is due to the fact that the natural spring constant of the first, second, and third rectangular shaped tabs 40 a, 40 b, 40 c, respectively, forces them to dig into the drilled bore 50.

The three rectangular shaped tabs 40 a, 40 b, and 40 c, respectively, are spaced along a tubular body 22 about sixty inches long such that the first tab 40 a is about four inches from the insertion end 32 of the tubular body 22, the second tab 40 b is about fourteen inches from the insertion end 32 of the tubular body 22, and the third tab 40 c is about twenty-four inches from the insertion end 32 of the tubular body 22. The rectangular shaped tabs 40 a, 40 b, and 40 c, respectively, can be sized such that the tab side edges 43 are about 0.5 inches long, and the tab free edge 45 is about 1.0 inch. The rectangular shaped tabs 40 a, 40 b, and 40 c, respectively, advantageously provide for a stabilizer 20 that, when installed in a mine, can support greater loads than stabilizers having smooth exterior surfaces. Of course, the dimensions may differ in other embodiments.

The friction stabilizer 20 further includes a weld ring 31 that in one embodiment is rectangular shaped, that is, its cross section is rectangular shaped as shown in FIGS. 31, 32, and 32 a. The rectangular shaped weld ring 31 has a weld ring gap space 39 and flat sides 31 a. The rectangular shaped weld ring 31 is positioned around exterior surface 26 of the tubular body 22 adjacent to the impact end 30 thereof, as shown in FIGS. 1-4. The weld ring gap space 39 is aligned with the tube gap space 28 defined in the tubular body 22. The rectangular shaped weld ring 31 is welded to the exterior surface 26 of the tubular body 22. The weld 49 that joins the tubular body 22 and rectangular shaped weld ring 31 is best shown in FIG. 5. It is noted that the weld ring gap space 39 and tube gap space 28 allow for the tubular body 22 to be compressed as it is driven into the drilled bore 50 having a bore diameter 51 less than the diameter of the tubular body 22. The rectangular shaped weld ring 31 is used for supporting a plate 58 in a manner to be described presently. In another embodiment, the rectangular shaped weld ring 31 and the tubular body 22 can be welded together, without the tube gap space 28 and weld ring gap space 39 being aligned.

FIG. 5 is a sectional view of the tubular body 22 taken along cut line 5-5 of FIG. 3, and FIG. 6 is a sectional view of the tubular body 22 taken along cut line 6-6 of FIG. 3.

It is noted that a circular shaped weld ring 37 having a circular shaped cross section, as shown in FIGS. 29, 30, and 30 a, can be successfully used in accordance with the present invention. However, the rectangular shaped weld ring 31 having a rectangular shaped cross section advantageously provides for a higher quality weld. This is due to the fact that a space 38 can form during the welding process under the weld 49 that joins the circular shaped weld ring 37 and the exterior surface 26 of the tubular body 22, as shown in FIG. 30 a. Additionally, to successfully weld the circular shaped weld ring 37 to the tubular body 22, the weld gun must be accurately positioned. However, such accurate positioning is oftentimes difficult to achieve, because the machinery that does the welding vibrates excessively. As a result, the majority of the weld 49 can end up on the circular shaped weld ring 37 or on the exterior surface 26 of the tubular body 22. Thus, the weld 49 may end up catching only one of the circular shaped weld ring 37 or exterior surface 26 of the tubular body 22, and/or a space 38 may be formed under the weld 49 as shown in FIG. 30 a.

The rectangular shaped weld ring 31 shown in FIGS. 31, 32, and 32 a advantageously has flat sides 31 a. As a result there is no space 38 between the flat surfaces 31 a rectangular shaped weld ring 31 and the exterior surface 26 of the tubular body 22, since these two surfaces make direct contact with one another leaving no room for a space 38 to form under the weld 49. Thus, a high quality weld 49 can be made between the flat surfaces 31 a of the rectangular shaped weld ring 31 and exterior surface 26 of the tubular body 22, even in the presence of the vibrations generated by the welding machines.

The above-described invention can be variously embodied. FIGS. 8-12 generally show a second embodiment of the friction stabilizer 20 a having rectangular shaped tabs 40. The tubular body 22 a of the second embodiment is substantially the same as the tubular body 22 of the first embodiment, in that the tubular body 22 a comprises an exterior surface 26, first and second gap space walls 27,29, respectively, a tube gap space 28, an impact end 30, an insertion end 32, a rectangular weld ring 31 having a weld ring gap space 39, a first portion 33, and a second portion 34 having a taper 35 having a notch 36. Each rectangular tab 40 of the second embodiment has parallel tab side edges 43 and a tab free edge 45. The second embodiment comprises a row 128 of rectangular shaped tabs 40 that are joined to the tubular body 22 a at bends 44, and which are spaced from one another at predetermined spaced intervals, designated I in FIG. 9, along the length L of the tubular body 22 a. It is noted that the row 128 extends from the side of the tubular body 22 a opposite the tube gap space 28. As shown in FIGS. 8-10, there are five rectangular shaped tabs 40 in the row 128 of course, in other embodiments, the row of tabs 128 may comprise fewer or more than five rectangular shaped tabs 40.

FIG. 11 is a sectional view of the tubular body of the second embodiment taken along cut line 11-11 of FIG. 10, and FIG. 12 is a sectional view of the tubular body of the second embodiment taken along cut line 12-12 taken of FIG. 8. The tubular body 22 a can be used for supporting the walls 52 and ceiling 54 of a mine 56 in the same manner as previously described in connection with the first embodiment.

FIGS. 13-17 generally show a third embodiment of the friction stabilizer 20 b with tabs. In this embodiment, the tubular body 22 b comprises triangular shaped tabs 41. The tubular body 22 b of the third embodiment is substantially the same as the tubular body 22 of the first embodiment, in that the tubular body 22 b comprises an exterior surface 26, first and second gap space walls 27,29, respectively, a tube gap space 28, an impact end 30, insertion end 32, a rectangular weld ring 31 having a weld ring gap space 39, a first portion 33, and a second portion 34 having a taper 35 having a notch. Each triangular shaped tab 41 of the third embodiment has two edges 46 that meet at a point 47, thus forming a triangle shape. The triangular shaped tabs 41 are joined to the tubular body 22 b at bends 44, as shown. There is a row 129 of triangular shaped tabs 41 that extend from the tubular body 22 b at predetermined spaced intervals, designated I in FIG. 13, along the length L of the tubular body 22 b. It is noted that the row 128 extends from the side of the tubular body 22 b opposite the tube gap space 28. As shown in FIGS. 13-17, there are five triangular shaped tabs 41 in the row 130. In other embodiments, the row of triangular shaped tabs 130 may comprise fewer or more than five triangular shaped tabs 41.

FIG. 16 is a sectional view taken along cut line 16-16 of FIG. 15, and FIG. 17 is a sectional view taken along cut line 17-17 of FIG. 13. The tubular body 22 b can be used in the same manner as described above in connection with the first embodiment for supporting the walls 52 and ceiling 54 of a mine 56.

FIGS. 18-22 generally show a fourth embodiment of the friction stabilizer 20 c with tabs. In the fourth embodiment, the tubular body 22 c comprises a plurality of rows 128 of rectangular shaped tabs 40. The rectangular shaped tabs 40 in each row 128 are spaced from one another, and the rows 128 are spaced about ninety degrees from one another about the exterior surface 26 of the tubular body 22 c, as viewed in sectional FIGS. 21 and 22. The tubular body 22 c of the fourth embodiment is substantially the same as the tubular body 22 of the first embodiment, in that the tubular body 22 c comprises an exterior surface 26, first and second gap space walls 27,29, respectively, a tube gap space 28, an impact end 30, insertion end 32, a rectangular weld ring 31 having a weld ring gap space 39, a first portion 33, and a second portion 34 having a taper 35 having a notch. Each rectangular shaped tab 40 of the fourth embodiment is joined to the tubular body 22 c at a bend 44, and extends in a direction toward the weld ring 31. As shown in FIGS. 18-22 there are three rows 128 of the rectangular shaped tabs 40, with five rectangular shaped tabs 40 per row. In other embodiments, there can even be more rows 128 of rectangular shaped tabs 40 provided for on the tubular body 22 c, or the number of rectangular shaped tabs 40 in each row may be increased or decreased.

FIG. 21 is a sectional view taken along cut line 21-21 of FIG. 20, and FIG. 22 is a sectional view taken along cut line 22-22 of FIG. 18. The tubular body 22 c can be used in the same manner as described above in connection with the first embodiment for supporting the walls 52 and ceiling 54 of a mine 56.

FIGS. 23-27 generally show a fifth embodiment of the friction stabilizer 20 d. In the fifth embodiment, the tubular body 22 d comprises a-plurality of rows 130 of triangular shaped tabs 41. The tubular body 22 d of the fifth embodiment is substantially the same as the tubular body 22 of the third embodiment, in that the tubular body 22 d comprises an exterior surface 26, first and second gap space walls 27,29, respectively, a tube gap space 28, an impact end 30, insertion end 32, a rectangular weld ring 31 having a weld ring gap space 39, a first portion 33, and a second portion 34 having a taper 35 having a notch. Each triangular shaped tab 41 of the fifth embodiment is joined to the tubular body 22 d at a bend 44, and extends away from the tubular body 22 d. The edges 46 of each triangular shaped tab 41 meet at a point 47. As shown in FIGS. 23-25 there are three rows 130 of the triangular shaped tabs 41, with five tabs 41 per row 130. The rows 130 of triangular shaped tabs 41 are spaced about ninety degrees from one another about the exterior surface 26 of the tubular body 22 d, as viewed in FIGS. 26 and 27. In yet other embodiments, there can even be more rows 130 of triangular shaped tabs 41 provided for on the tubular body 22 d.

FIG. 26 is a sectional view taken along cut line 26-26 of FIG. 25, and FIG. 27 is a sectional view taken along cut line 27-27 of FIG. 23. The tubular body 22 d can be used in the same manner as described above in connection with the first embodiment for supporting the walls 52 and ceiling 54 of a mine 56.

Shown in FIG. 27A is a sixth embodiment of the friction stabilizer 20 e wherein the tubular body 22 e has a plurality of differently shaped tabs 25. The tabs 25 may be curved shaped tabs, rectangular shaped tabs, triangular shaped tabs, polygonal shaped tabs, U-shaped tabs, tabs having both curved portions and linear portions, semi-circular shaped tabs, hook shaped tabs, parabolic shaped tabs, combinations of the above, or any other shaped tab that inhibits the withdrawal of the friction stabilizer 20 e from the drilled bore 50 in the mine 56. The above-described tabs 25 may extend in patterns, rows, series, or randomly from the exterior surface 26 of the friction stabilizer 20 e. As shown in FIG. 27A, a plurality of differently shaped tabs 25, as described above, extend from the friction stabilizer 20 e. In other embodiments, a single tab 25, for example a rectangular shaped tab 40 or triangular shaped tab 41, may extend from the exterior surface 26 of the friction stabilizer 20. The single tab 25 may be any of the above shapes. Thus, the present invention has significant versatility and may be variously embodied, and all of these embodiments are within the scope of the present invention.

To manufacture the friction stabilizer with tabs 20, reference is made to the schematic shown in FIG. 28. The process or method begins with a coil of metal, preferably steel or a steel alloy 100. First, a planar or flat strip of steel 102 pulled from the steel coil, in the direction indicated-by the arrows in FIG. 28. The strip 102 has a width, designated W in FIG. 7, that is about three inches wide in the first embodiment. In other embodiments, the width could be more than or less than three inches, depending on the particular application or customer requirement.

As the strip of steel 102 is pulled from the coil 100, it moves onto a conveyor 105. The strip of steel 102 passes through a pressing machine 104 wherein the tab side edges 43 and tab free edges 45 are pressed into the flat strip of steel 102. Pressing machines are well known to those having ordinary skill in the art. It is to be understood that the tab side edges 43 and free edges 45 may also be laser cut or otherwise formed in the sheet of steel 102 at this point in the manufacturing process, by the use of a laser or other device. The shape of the tab 25 is thus formed in the sheet of steel 102. It is to be further understood that any desired shape of the tab 25 could be formed by the pressing machine 104.

The strip 102 is next moved by conveyor 105 through a punching machine 106 where the notches 36 are punched out of or otherwise formed into the flat strip 102. Punching machines 106 are known to those having ordinary skill in the art. In another embodiment, the notches 36 could be punched from the strip 102 first, and then the tabs 40 pressed in the strip 102.

A means for measuring 108 continuously measures the length of the strip 102 prior to the punching machine 106 so that the notch 36 can be punched in the strip 102 at the desired position in the strip 102. The final length of the friction stabilizer with tabs 20 is thus determined by the notch 36 location in the strip 102. Next, the strip 102 passes from the punching machine 106 and is moved by conveyor 105 through a cold roll forming mill 110. The cold roll forming mill 110 comprises a series of stands having top and bottom rolling die 112 a, 112 b, respectively. Cold roll forming mills 110 are known to those having ordinary skill in the art.

As the strip 102 progresses from stand to stand in the cold rolling mill 110 it is formed into a tubular body 22 having the above-described tube gap space 28. At the same time, the rectangular shaped tabs 40 begin to move away from the exterior surface 26 of the continuous tubular body 22 z that is being formed in the cold rolling mill 110. This is attributed to the fact that the natural spring constant-of the steel, steel alloy, galvanized steel, or other metal from which the continuous tubular body 22 z, is made causes the rectangular shaped tabs 40 to extend from the exterior surface 26 thereof. It is noted that if the tabs do not extend out, then they may be mechanically pushed out of the tubular body 22.

As the continuous tubular body 22 z exits the cold roll forming mill 110, the tabs 40 extend from it as previously described and it has notches 36, but still has to be cut to the predetermined length. The continuous tubular body 22 z is then moved by conveyor 105 through a cut-off press 114, where the notch 36 in the tubular body 22 signals the cut-off press 114 to cut the tubular body 22 to the predetermined length at the notch 36. The length of the tubular body may be about 60 inches as shown in FIG. 1 and described in the first embodiment, but in other embodiments, the tubular body 22 can be formed to have a length of 18 inches, 24 inches, over six feet, or any length required for the particular job, application, or customer order.

The tubular body 22 is then placed on conveyor 105 and transported to a swaging station 116. At the swaging station 116, the insertion end 32 of the tubular body 22, where the notch 36 is located, has pressure applied to it such that the taper 35 is formed at the insertion end 32. It is noted that the notch 36 provides the space for the taper 35 to be formed in the section portion 34 in the swaging station 116. The tubular body 22 is then moved by a conveyor 105 to a welding station 118. At the welding station 118 the rectangular shaped weld ring 38 is fitted about the impact end 30 of the tubular body 22, such that the weld ring gap space 39 aligns with the tube gap space 28. While held in this position by the welding machine, the tubular body 22 and weld ring 38 are welded together, and thus joined by a weld 49. Welding stations 118 are well known to those having ordinary skill in that art. After welding, the weld ring 38 is joined with the impact end 30 of the tubular body 22. The weld ring gap space 39 may be laser cut or punched out of the weld ring 38.

After exiting the welding station 118, the tubular bodies 22 are moved by conveyor 105 to a packing station 120 having an automatic packaging machine 121. Every other tubular body 22 is then turned end over end and automatically packaged in bundles 122 of, for example, six tubular bodies 22, by the automatic packaging machine 121. Automatic packaging machines 121 are known to those having ordinary skill in the art. The bundles 122 are transported by conveyor 105 to a shipping station 124, placed in crates 126, and shipped.

After the friction stabilizer with tabs 20 has been rolled and formed as described above, the tabs 40 may have sharp tab side edges 43 and tab free edges 45. Thus, another step that may be included in the process or method is a grinding step, which takes place prior to automatic packing of the tubular bodies 22. During the grinding step, any sharp tab side edges 43 and tab free edges 45 are ground down and dulled, thus decreasing the likelihood of a worker being cut or injured by the tabs 40.

The same general method or process is carried out to make the other embodiments of the friction stabilizer having tabs 20, described above. For each embodiment the pressing machine 104 would stamp, punch, or cut edges in the strip of steel 102 such that the tab 25 of desired shape may be formed (rectangular shaped tabs, triangular shaped tabs, curved shaped tabs, polygonal shaped tabs, U-shaped tabs, tabs having both curved portions and linear portions, semi-circular shaped tabs, hook shaped tabs, parabolic shaped tabs, combinations of the above, or any other shaped tab that inhibits the withdrawal of the friction stabilizer with tabs 20 from the drilled bore 50 in the mine 56).

To use the friction stabilizer 20 with tabs, a drilled bore 50 is made in a wall 52 or ceiling 54 of a mine 56 having a floor 55, as shown in FIG. 37. It is understood that forming a drilled bore 50 in a mine 56 is known to those having ordinary skill in the art. The drilled bores 50 are made in the 52 ceilings and/or walls 54 of the mine 56. The drilled bore 50 has a diameter, designated B in FIG. 37, which is less than the diameter of the tubular body 22, designated S and shown in FIG. 4.

As shown in FIGS. 33 and 34, a plate 58 having a plate opening 60 is provided. The plate 58 has planar surfaces 59, and is of metal, preferably steel, steel alloys, stainless steel, and galvanized steel. The plate opening 60 is sized such that the friction stabilizer 22 can be moved through the opening 60. But, the weld ring 38 is too large to pass through the plate opening 60. The plate 58 is positioned such that the opening 60 is brought into alignment with the drilled bore 50 the wall 52 or ceiling 54, as the case may be, of the mine 56, and held in that position. Since the taper 35 at the insertion end 32 of the tubular body 22 has a diameter less than the diameter, designated B, of the drilled bore 50, the insertion end 30 of the tubular body 22 can be readily moved into the drilled bore 50. In particular, the insertion end 32 is moved through the opening 60 in the plate 58, such that the taper portion 34 is moved into the drilled bore 50. However, because the diameter, designated S, of the tubular body 22 is greater than the diameter, designated B, of the drilled bore 50, the first portion 33 of the tubular body 22 must be driven into the drilled bore 50.

To accomplish this, the impact end 30 of the tubular body 22 is driven by a pneumatic hammer, hydraulic hammer, or other means for hammering or driving (not shown) into the drilled bore 50. The tubular body 22 compresses radially inward as it is driven into the drilled bore 50, such that the tube gap space 28 decreases. Additionally, the tabs 40 fold in a direction toward the exterior surface 26 of the tubular body 22, and do not resist insertion of the tubular body 22 into the drilled bore 50. As a result of tubular body 22 being driven into the lesser diameter drilled bore 50, the tubular body compresses radially inward and the tube gap space 28 and weld ring gap space 39 both decrease. The tubular body 50 then exerts expanding forces against the adjacent surrounding drilled bore wall 51.

Also, in another embodiment shown in FIGS. 35 and 36, the plate can be a domed-shaped plate 64 having a domed portion 65. The domed portion 65 has an opening 67 for receiving the friction stabilizer 20 there-through. Contact surfaces 69 are provided on the domed plate 64 and are used for contacting the wall 52 or ceiling 54 of the mine 56.

It is noted that as the stabilizer 20 with tabs is driven into the drilled bore 50, the rectangular shaped tabs 40 move downwardly toward the tubular body 22 and do not obstruct insertion into the drilled bore 50. However, once driven into the drilled bore 50, the tabs 40 force outwardly from the tubular body 22 due to the natural spring constant of the steel or other material from which the stabilizer with tabs 20 is made. The tabs 40 contact the adjacent surrounding drilled bore wall 51 and dig into it, resulting in the friction stabilizer with tabs 20 being held in the drilled bore 50 by both a friction fit created by the expanding forces generated by the tubular body 22, and by the tabs 40 digging into the drilled bore 50.

Then, if force is applied to remove the friction stabilizer with tabs 20, the tabs 40 immediately dig into the adjacent drilled bore wall 51 and work against removal of the stabilizer with tabs 20 from the drilled bore 50. This significantly reduces the likelihood that the stabilizer with tabs 20 will work its way out of the drilled bore 50 and advantageously significantly increases the amount of weight or force the friction stabilizer with tabs 20 can support. Thus the friction stabilizer with tabs 20 advantageously decreases the likelihood of a cave-in of walls 52 and/or ceilings 54 of a mine 56.

In addition, the plate 58, which is trapped between the weld ring 38 and mine wall 52 or ceiling 54 after installation, provides for additional support of the surrounding mine walls 52 and ceilings 54, as the case may be. It is noted that the plate 58 is supported by the weld ring 38. Thus, if the rock above the plate 58 fractures and weakens, the plate 58 supports the rock, and the plate 58 in turn is supported by the friction stabilizer with tabs 20 in the drilled bore 50, and the tabs 40 advantageously constantly working against removal of the friction stabilizer with tabs 20 from the drilled bore 51.

The present invention also provided for a mine support system 80. In particular, the friction stabilizer 20 having tabs can be-positioned and spaced from one another in drilled bores 50 that are spaced about three feet apart from one another in all directions, for example in the walls 52 and ceiling 54 of the mine 56. A wire mesh 65 is provided. The wire mesh 65 is positioned adjacent to the walls 52 and ceiling 54 of the mine 56. Then the plates 58 are aligned with the drilled bores 50 in the manner described above. Next, the friction stabilizer 20 is driven into the drilled bore 50 in the manner previously described. The wire mesh 65 extends between all of the plates 58 in the mine and is trapped between the plates 58 and the mine wall 52 and plates 58 and ceiling 54. The wire mesh 65 serves to support any rocks or debris that break off of the walls 52 or ceiling 54 of the mine 56. The ability of the wire mesh 65 to support greater loads is advantageously increased, because the friction stabilizer having tabs 40 can support a greater load from the wire mesh 65. Thus, the stabilizer with tabs 20 can be used as an integral part of a mine support system 80 to prevent mine 56 cave-ins.

It is noted that the above-described support system 80 can be used in combination with any of the above-described embodiments of the friction stabilizer having tabs 20.

As previously described, in other embodiments the tabs 25 can be any of a plurality of different shapes (rectangular shaped tabs, triangular shaped tabs, curved shaped tabs, polygonal shaped tabs, U-shaped tabs, tabs having both curved portions and linear portions, semi-circular shaped tabs, hook shaped tabs, parabolic shaped tabs, combinations of the above, or any other shaped tab that inhibits the withdrawal of the friction stabilizer with tabs 20 from the drilled bore 50 in the mine 56).

Additionally, in other embodiments, the rectangular shaped tabs 40 can be formed such that they extend from the tubular body 22 anywhere from the exterior surface 26 of the tubular body 22 including randomly or in patterns. The same is true with respect to all of the above-described differently shaped tabs 25, in that they may all extend from the tubular body 22 randomly or in patterns. Also, the number of tabs 25 can be varied regardless of the shape of the tab 25. In addition, the size of the tab 25 can be varied depending on the requirements of the particular application in which the stabilizer 20 will be deployed. In yet other embodiments a single tab 25 having any of the above described shapes may extend from the tubular body 22. Also, in other embodiments the length of the taper 35 of the second portion 34 may be increased or decreased.

Also, the diameter of the tubular body 22 of the friction stabilizer with tabs 20 may be more or less than an inch, but in other embodiments the diameter of the stabilizer may be customized to suit particular needs for a particular application. The tubular body 22 can comprise various lengths L, for example the sixty inch length described above, or a length required for a particular application. For example, some mines 56 may require tubular bodies 22 having lengths of twelve, eighteen, or forty inches, whereas other mines 56 may require tubular bodies 22 having lengths of over two hundred inches. The friction stabilizer having tabs 20 may be used in these mining applications. The material from which the stabilizer 20 and weld ring 38 are made comprises metal, such as steel, steel alloys, galvanized steel, high strength steel, metal and metal alloys.

Although a friction stabilizer 20 with tabs has been described, the present invention could be otherwise embodied without departing from the principles thereof, and all such embodiments come with the scope and sprit of the present invention for a friction stabilizer 20 having tabs. 

1. A friction stabilizer for installation in a structural body, the friction stabilizer comprising: a) a tubular body comprising first and second portions along the axial length thereof and having an exterior surface, the second portion having a taper, b) the first portion having an impact end and the second portion having an insertion end, and c) a tab on the tubular body and the tab extending outward from the exterior surface of the tubular body in a direction toward the impact end and away from the insertion end.
 2. A friction stabilizer comprising according to claim 1 further comprising a weld ring joined to the exterior surface of the first portion.
 3. The friction stabilizer according to claim 1 wherein the tubular body further comprises a first gap space wall and a second gap space wall spaced apart from one another by a tube gap space and wherein the tube gap space is used for allowing the tubular body to be compressed radially inward.
 4. The friction stabilizer according to claim 2 wherein the weld ring has a weld ring gap space and wherein the weld ring is joined to exterior surface of the tubular body such that the weld ring gap space and tube gap space are aligned and wherein the weld ring gap space is used for allowing the weld ring to be compressed radially inward.
 5. The friction stabilizer according to claim 4 wherein the weld ring comprises a rectangular shaped cross section.
 6. The friction stabilizer according to claim 4 wherein the weld ring comprises a circular shaped cross section.
 7. The friction stabilizer according to claim 1 wherein the tab comprises a rectangular shaped tab extending from the first portion of the tubular body.
 8. The friction stabilizer according to claim 1 wherein the tab comprises a triangular shaped tab.
 9. The friction stabilizer according to claim 1 wherein the tab comprises a polygonal shaped tab.
 10. The friction stabilizer according to claim 1 wherein the tab comprises a U-shaped tab.
 11. The friction stabilizer according to claim 1 wherein the tab comprises a semi-circular shaped tab.
 12. The friction stabilizer according to claim 1 wherein the tab comprises a curved tab or parabolic shaped tab.
 13. The friction stabilizer according to claim 1 wherein the tab comprises a shape such that the removal of the tubular body from a drilled bore in the structural body is inhibited.
 14. The friction stabilizer according to claim 1 further comprising a notch used for allowing the taper in the second portion to be formed.
 15. The friction stabilizer according to claim 7 wherein the rectangular shaped tab is connected to the tubular body at a bend and the rectangular shaped tab further comprises parallel tab side edges and a tab free edge connecting between the tab side edges and opposite to the bend.
 16. A friction stabilizer for supporting mine walls and ceilings, the friction stabilizer comprising: a) a tubular body comprising first and second portions along the axial length thereof, an exterior surface, the first portion having an impact end and the second portion having an insertion end and a taper, and b) a first rectangular shaped tab, a second rectangular shaped tab, and a third rectangular shaped tab each joined to the tubular body at bends and extending outward from exterior surface of the first portion of the tubular body in a direction toward the impact end of the tubular body.
 17. The friction stabilizer according to claim 16 wherein each of the first rectangular shaped tab, the second rectangular shaped tab, and third rectangular shaped tab comprises parallel tab side edges and a tab free edge connecting between the parallel tab side edges and opposite to the bend.
 18. The friction stabilizer according to claim 17 wherein the parallel tab side edges are about 0.5 inches and the tab free edge is about 1.0 inch.
 19. The friction stabilizer according to claim 16 wherein the first tab is about 4.0 inches from the insertion end, the second tab is about 14.0 inches from the insertion end, and the third tab is about 24.0 inches from the insertion end of the tubular body.
 20. The friction stabilizer according to claim 19 wherein the tubular body has a length of about 60 inches.
 21. The friction stabilizer according to claim 16 further comprising a weld ring having a weld ring gap space and wherein the tubular body has a tube gap space with the weld ring joined to the exterior surface of the first portion such that the weld ring gap space and tube gap space are aligned and wherein the tube gap space is used for allowing the tubular body to be compressed radially inward.
 22. The friction stabilizer according to claim 16 wherein the tubular body further comprises a first gap space wall and a second gap space wall spaced apart from one another by a tube gap space and wherein the tube gap space is used for allowing the tubular body to be compressed radially inward.
 23. The friction stabilizer according to claim 21 wherein the weld ring comprises a rectangular shaped cross section.
 24. The friction stabilizer according to claim 21 wherein the weld ring comprises a circular shaped cross section.
 25. A method of making a friction stabilizer for installation in a structural body, the method comprising the steps of: providing a coil of metal and unrolling the coil of metal into a strip, pressing the shapes of a tab to be formed into the strip of metal, moving the strip of metal through cold rolling dies and forming the strip of steel into a tubular body having an exterior surface and a first portion and a second portion having a taper.
 26. The method of making a friction stabilizer according to claim 25 wherein the step of pressing the shape of the tab to be formed includes pressing a rectangular shape into the strip of metal.
 27. The method of making a friction stabilizer according to claim 25 wherein the step of pressing the shape of the tab to be formed includes pressing a triangular shape into the strip of metal.
 28. The method of making a friction stabilizer according to claim 25 wherein the step of pressing the shape of the tab to be formed includes pressing a polygonal shape into the strip of metal.
 29. The method of making a friction stabilizer according to claim 25 wherein the step of pressing the shape of the tab to be formed includes the step of pressing a curved shaped tab into the sheet of metal.
 30. The method of making a friction stabilizer according to claim 25 wherein the step of pressing the shape of the tab to be formed includes the step of pressing a plurality of shapes of tabs to be formed into the tubular body.
 31. The method of making a friction stabilizer according to claim 25 comprising the further steps of forming the tubular body to have a tubular body gap space and providing the weld ring with a weld ring gap space and aligning the tubular body gap space and weld ring gap space before connecting the weld ring to the exterior surface of the first portion.
 32. The method of making a friction stabilizer according to claim 25 comprising the further step of punching a notch in the strip of metal.
 33. The method of making a friction stabilizer according to claim 32 comprising the further step of using the notch for cutting the tubular body at a predetermined length such that the tubular body has an insertion end having the notch and an impact end opposite the insertion end.
 34. The method of making a friction stabilizer according to claim 33 comprising the further step of swaging the insertion end of the tubular body and to form the taper in the tubular body.
 35. The method of making a friction stabilizer according to claim 25 comprising the further step of providing a weld ring and joining the weld ring to the exterior surface of first portion.
 36. A method of preventing a mine having a ceiling and walls from caving-in, the method comprising the steps of: providing a drilled bore in the ceiling and/or wall of the mine, providing a tubular body comprising an impact end and an insertion end and wherein the tubular body has a first portion and has a second portion provided with a taper, providing the tubular body with a tube gap space and an exterior surface and providing the tubular body with a tab extending from the exterior surface in a direction toward the impact end of the tubular body, providing a weld ring connected to the exterior surface of the first portion of the tubular body, providing a plate having an opening, positioning the plate opening such that it is aligned with the drilled bore, aligning the impact end of the tubular body with the opening in the plate and hammering the impact end of the tubular body and driving the tubular body through the plate opening and into the drilled bore, capturing the-plate between the weld ring and surrounding mine and the plate used for supporting the mine, and using the tab for preventing the tubular body from being withdrawn from the drilled bore when load is applied to the plate.
 37. The method of stabilizing a mine having walls and a ceiling according to claim 36 wherein the tab comprises a rectangular shaped tab.
 38. The method of stabilizing a mine having walls and a ceiling according to claim 36 wherein the tab comprises a triangular shaped tab.
 39. The method of stabilizing a mine having walls and a ceiling according to claim 36 wherein the shape of the tab is polygonal
 40. The method of stabilizing a mine having walls and a ceiling according to claim 36 wherein the shape of the tab is curved.
 41. The method of stabilizing a mine having walls and a ceiling according to claim 36 wherein the shape of the tab is such that it prevents removal of the tab from the drilled bore.
 42. The method of stabilizing a mine having walls and a ceiling according to claim 36 wherein the weld ring has a rectangular cross section.
 43. The method of-stabilizing a mine having walls and a ceiling according to claim 36 wherein the weld ring has a weld ring gap space that is aligned with the tubular body gap space.
 44. A mine support system for use in a mine having drilled bores in the mine ceiling and walls, the mine support system comprising: a) a plurality of tubular bodies each comprising an impact end, an exterior surface, and an insertion end and each tubular body further comprising a first portion and a second portion having a taper, b) the tubular bodies each comprising a tubular body gap space and a notch in the second portion forming the taper, c) a plurality of tabs connected on each of the tubular bodies and the tabs extending outwardly from exterior surface of the tubular bodies in a direction toward the impact ends of the tubular bodies, d) weld rings connected to the exterior surfaces of the first portions of the tubular bodies, e) plates having plate openings, f) a wire mesh, and g) wherein the tubular bodies are positioned in the drilled bores such that the tapers of the second portions are positioned farthest into the drilled bores, and such that the weld rings contact and support the plates and the plates contact the and support the wire mesh that is captured between the plates and surrounding mine walls.
 45. The mine support system according to claim 44 wherein the shape of the tabs are rectangular.
 46. The mine support system 44 wherein the shape of the tabs are triangular.
 47. The mine support system according to claim 44 wherein the shapes of the tabs are polygonal.
 48. The mine support system according to claim 44 wherein the shape of the tabs are curved.
 49. The mine support system according to claim 44 wherein the shape of the tabs are such that they prevent removal of the tab from the drilled bore.
 50. The mine support system according to claim 44 wherein the weld rings each have a rectangular cross section.
 51. The mine support system according to claim 50 wherein the weld rings have weld ring gap spaces that are aligned with the tubular body gap spaces. 